Traditionally, dimensional lumber is produced for two main purposes:                “Structural” lumber is produced and graded for properties of strength and stiffness. “Early Wood” (core wood) has lower basic properties than “Late wood” and inclusion of “Early Wood” in a piece of dimensional lumber can cause strength down grading. Defects, (knots, resin pockets, bark inclusions, decay, insect attack, shakes, etc.) also lead to down grading although in pine knots have the dominant influence. These defects tend to be scattered through the length of a piece of lumber and lead to down grading on the basis of “a piece is only as strong as the weakest link”.        “Appearance” lumber is produced and selected on the basis of surface appearance. Appearance grades can range from “Clears” for furniture type end uses to “merchantable” for exterior finishing. The important features are lack of defects particularly those that affect the surface finish. Inter-grown knots do not result in a down grade and for unpainted surfaces can be considered an attractive feature.        
For any particular feedstock (log grade) and cutting regime a wide range of properties will be produced. The total output can be tested and graded or inspected and graded after initial sawing. Even within grades there is a wide range of properties.
This range of properties is produced when a log is broken down into (typically 100×50 mm) sections. If a log is broken down into even smaller sections (say 50×7 mm) we have found there will be a greater spread of properties.
With traditional dimensional lumber the output range is predominantly influenced by selection of feedstock (tree age, position in the tree, silver-culture regime) although there is some minor influence from the sawing patterns selected.
Examples of efforts in the past to meet demand for products other than pulp and paper have included dry fibre separation and reconstitution procedures as typified by U.S. Pat. No. 4,061,819 (Barnes). (MacMillan Bloedel Ltd) and LSL and LVL procedures as used by Trus Joist Corporation of Boise, Id., USA.
Weyerhaeuser Company PCT/US98/11566 (WO98/56549) discloses composite lumber products based on sweep avoiding slat production from flitches derived from round logs.
MacMillan Bloedel Limited in NZ 241289 (also referring Holman U.S. Pat. No. 4,255,477 in respect of panel or strand lumber products and U.S. Pat. Nos. 4,610,913 and 4,751,131 of Barnes in respect of the use of longer wafers in higher strength lumber product production) discloses composite wood products of improved strength where cutting avoids surface and internal damage to the veneer, wafers and strands.
Weyerhaeuser Company PCT/US97/15250 (WO98/10157) discloses engineered structural wood products and related methods reliant on different rectangular board orientations in the resultant laminated product.
U.S. Pat. No. 5,500,070 (Traben et al) discloses knife cutting of thin boards for the purpose of manufacturing multilayered laminated products.
Nevertheless efficiencies of usage while still providing acceptable engineered lumber products especially to customer demand can still further be improved where source materials are single or multi forest derived single or multi grade logs.
The present invention as an object or an alternate object addresses issues of waste reduction during the production of dimensional lumber and in so doing preferably improves usage of feedstock for the purpose of value enhancement.
The present invention has as one or one alternative object a method of producing laminated elongate products and to related products, practices and procedures reliant on a performance advantage over mere random assembly.
The present invention has as one or an alternative object an overall process capable of better using logs or part of tree stems (and particularly those of conifers such as Radiata Pine, Loblolly Pine, Douglas Fir, Spruce, etc.) which might otherwise only be suitable for chipping or non structural or non appearance lumber.
Another or an alternative object therefore, as will become apparent, is the conversion of low grade wood into high grade products preferably at an efficient yield from trees.